1. Field of the Invention
The present invention related to a wheel suspension of vehicles such as automobiles, and more particularly, to an improvement of a wheel suspension assembled from a pair of trailing arms and a torsion beam by welding, the improvement concerning the durability of the weld portion.
2. Description of the Prior Art
As a type of wheel suspension of four wheeled vehicles, there is known a torsion beam type wheel suspension for a pair of front wheels or a pair of rear wheels which is constructed from a pair of trailing arms arranged to extend substantially longitudinally relative to the vehicle body in a laterally symmetrical relationship thereto, each first end of the trailing arms being pivotably mounted to the vehicle body, while each second end thereof opposite to the first end rotatably supporting a corresponding one of the pair of front or rear wheels, and a torsion beam arranged to extend substantially laterally relative to the vehicle body between the pair of trailing arms with opposite ends thereof being firmly connected to the pair of trailing arms by welding, so as to form a suspension link assembly having a form of substantially the letter of H or a staple according to the longitudinal position of the torsion beam along the trailing arms. The wheel suspension of this type provides an advantage that, when the vehicle is driven on a rough ground presenting different irregularities to the left and right wheels, the vehicle body is less liable to a heavy rolling of the pair of wheels.
However, the weld portion, or weld seam, along which each of the opposite ends of the torsion beam abutted against a middle portion of each corresponding one of the trailing arms is welded thereto is subjected to a high tensile stress, when the pair of trailing arms are substantially biased relative to one another such that, for example, the left wheel bounds due to running on a convex irregularity, while the right wheel rebounds due to dropping in a concave irregularity, or vice versa, thereby substantially twisting the torsion beam, or when a strong lateral force is applied to the wheels due to a sharp turning of the vehicle, thereby applying a lateral bending to the trailing arms around the joint portion between the trailing arms and the torsion beam. It will be noted that a weld seam formed along a surface border of two abutted members is particularly sensitive to a force acting to separate one from the other of the two members.